Spectroscopic Classification of DLT18a/AT2018is as a faint type II supernova or luminous blue variable outburst
ATel #11210; D. Sand (Arizona), S. Valenti (UC Davis), J. Andrews (Arizona), J. Strader, L. Chomiuk (Michigan State), S. Wyatt (Arizona)
on 21 Jan 2018; 19:30 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: David Sand (email@example.com)
Subjects: Optical, Supernovae, Transient
We obtained an optical spectrum of DLT18a/AT2018is (Atel #11207) on UT 2018 January 21.3 with the Goodman Spectrograph on the SOAR telescope. The spectrum displays a blue continuum with prominent Halpha, Hbeta and He lines, with approximate velocities of 4000 km/s (after a host-redshift correction). Spectral classification was performed with SNID (Blondin and Tonry 2007, ApJ, 666, 1024), with good matches to faint type II SNe about 1-2 weeks after explosion. The spectrum is also similar to a luminous blue variable outburst, such as NGC4559_OT.
Given the current absolute magnitude of this transient, M_V~-13, either interpretation is plausible. We encourage further observations.